<template>
  <h2>当前求和为：{{ sum }}</h2>
  <button @click="sum++">点我+1</button>
  <hr />
  <h2>当前的信息为：{{ msg }}</h2>
  <button @click="msg += '！'">修改信息</button>
  <hr />
  <h2>姓名：{{ person.name }}</h2>
  <h2>年龄：{{ person.age }}</h2>
  <h2>薪资：{{ person.job.j1.salary }}K</h2>
  <button @click="person.name += '~'">修改姓名</button>
  <button @click="person.age++">增长年龄</button>
  <button @click="person.job.j1.salary++">涨薪</button>
</template>

<script>
import { ref, reactive, watch, watchEffect } from "vue";
export default {
  name: "Demo",
  setup() {
    //数据
    let sum = ref(0);
    let msg = ref("你好啊");
    let person = reactive({
      name: "张三",
      age: 18,
      job: {
        j1: {
          salary: 20,
        },
      },
    });

    //监视
    /* watch(sum,(newValue,oldValue)=>{
				console.log('sum的值变化了',newValue,oldValue)
			},{immediate:true}) */
    // 自动开启immediate:true

    // watchEffect的套路是：不用指明监视哪个属性，监视的回调中用到哪个属性，那就监视哪个属性。
    watchEffect(() => {
      const x1 = sum.value;
      const x2 = person.job.j1.salary;
      console.log("watchEffect所指定的回调执行了");
    });

    //返回一个对象（常用）
    return {
      sum,
      msg,
      person,
    };
  },
};
</script>

